CVE-2026-55244

MEDIUMPre-NVD 5.05.0—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 5.0 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2% (6th percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
5.0EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 5.0Exploit: Elevated riskExposed services: Not assessed

A fix is available — apply it.

ASTEVAL is an evaluator of Python expressions and statements. Prior to 1.0.9, FROM_PY in asteval/astutils.py exposes BaseException, SystemExit, KeyboardInterrupt, and GeneratorExit to expressions evaluated by asteval.Interpreter.eval(), while run() and eval() in asteval/asteval.py catch Exception rather than these non-Exception BaseException subclasses. When an attacker-controlled expression raises one of these classes, on_raise() passes the class to raise_exception(), and the resulting exception bypasses the interpreter's safety handlers and propagates into the calling application. A consuming service that evaluates untrusted expressions can therefore be terminated or have signal and cleanup handling disrupted, causing denial of service. The separately documented read-only open() capability is not part of this vulnerability. This issue is fixed in version 1.0.9.

CVSS v3
5.0
EG Score
5.0MEDIUMmedium confidence
EG Risk
39
EG Risk 39/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity50% × 45%
Exploitation40% × 40%
Automatability0% × 15%
CISA SSVC: Track at low or medium mission impact; Track* at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
6th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Track* at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

August 20, 2026

Last Modified

September 30, 2026

Advisory Details (5)

Auto-updated Sep 14, 2026
🔬 Proof of concept available. Patch available. Sources: github_pr, github_release, github, github_commit.
github Patch Available🟡 PoC Available

Sandbox Escape via BaseException Subclasses in asteval 1.0.8 · Advisory · lmfit/asteval · GitHub

Affected: 1.0.6. This vector is present in

https://github.com/lmfit/asteval/security/advisories/GHSA-89v8-rhwq-hf77
github_release Patch Available

1.0.9

Patch available: lmfit/asteval 1.0.9

https://github.com/lmfit/asteval/releases/tag/1.0.9
github_pr Patch Available

Fix exiting exceptions

Patch available: lmfit/asteval 1.0.9 (PR #153 merged 2026-06-11)

https://github.com/lmfit/asteval/pull/153
github_commit Patch Available

commit c49c99a67acb (lmfit/asteval)

Patch available: lmfit/asteval 1.0.9 (contains commit c49c99a67acb)

https://github.com/lmfit/asteval/commit/c49c99a67acb63eb7410231932250bd820380e45
github_commit Patch Available

commit 9c625b3674f8 (lmfit/asteval)

Patch available: lmfit/asteval 1.0.9 (contains commit 9c625b3674f8)

https://github.com/lmfit/asteval/commit/9c625b3674f8d05f206708bb85afca17a87694a4

Vendor Advisories for CVE-2026-55244(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(4 across 4 ecosystems)
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
python-asteval0.9.28-1, 0.9.30-1, 0.9.31-1, 1.0.6-1, 1.0.6-2
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
python-asteval1.0.6-2
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
python-asteval1.0.6-2
  • every version on: no fix on record
—
PyPI(1)
PackageVulnerable rangeFix by version rangeDependents
asteval0.9 ... 1.0.8 (43 versions)
  • every version up to 1.0.9: fixed in 1.0.9
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 14× in last 7d / 36× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-05 05:00 UTCEG score recompute
  2. 2026-10-04 23:22 UTCEPSS rescore
  3. 2026-10-04 02:42 UTCEG score recompute
  4. 2026-10-03 14:26 UTCEPSS rescore
  5. 2026-10-03 00:40 UTCEG score recompute
  6. 2026-10-02 17:56 UTCEPSS rescore
  7. 2026-10-01 21:29 UTCEG score recompute
  8. 2026-10-01 19:50 UTCEPSS rescore
  9. 2026-09-30 18:10 UTCEG score recompute
  10. 2026-09-30 15:03 UTCEPSS rescore
  11. 2026-09-30 09:19 UTCEG score recompute
  12. 2026-09-29 15:22 UTCEPSS rescore
  13. 2026-09-29 07:18 UTCEG score recompute
  14. 2026-09-28 13:51 UTCEPSS rescore
  15. 2026-09-28 05:03 UTCEG score recompute
  16. 2026-09-27 13:48 UTCEPSS rescore
  17. 2026-09-27 03:02 UTCEG score recompute
  18. 2026-09-26 15:59 UTCEPSS rescore
  19. 2026-09-25 11:48 UTCEG score recompute
  20. 2026-09-24 14:04 UTCEPSS rescore
  21. 2026-09-24 09:32 UTCEG score recompute
  22. 2026-09-23 17:54 UTCEPSS rescore
  23. 2026-09-23 07:26 UTCEG score recompute
  24. 2026-09-22 05:24 UTCEG score recompute
  25. 2026-09-21 03:23 UTCEG score recompute
Show 12 more
  1. 2026-09-20 20:16 UTCEPSS rescore
  2. 2026-09-20 01:22 UTCEG score recompute
  3. 2026-09-18 23:20 UTCEG score recompute
  4. 2026-09-18 19:28 UTCEPSS rescore
  5. 2026-09-17 21:19 UTCEG score recompute
  6. 2026-09-17 19:31 UTCEPSS rescore
  7. 2026-09-16 17:52 UTCEG score recompute
  8. 2026-09-16 16:58 UTCEG score recompute
  9. 2026-09-16 14:08 UTCEPSS rescore
  10. 2026-09-16 05:15 UTCEPSS rescore
  11. 2026-09-14 20:27 UTCEG score recompute
  12. 2026-08-20 17:42 UTCEG score recompute

Related CVEs(same product + same CWE)

Same product

1 shown

Debian:12:python-asteval

Frequently asked(5)

What is CVE-2026-55244?
CVE-2026-55244 is a medium vulnerability published on August 20, 2026. ASTEVAL is an evaluator of Python expressions and statements. Prior to 1.0.9, FROMPY in asteval/astutils.py exposes BaseException, SystemExit, KeyboardInterrupt, and GeneratorExit to expressions evaluated by asteval.Interpreter.eval(), while run() and eval() in asteval/asteval.py catch Exception…
When was CVE-2026-55244 disclosed?
CVE-2026-55244 was first published on August 20, 2026, with the most recent update on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55244 actively exploited?
CVE-2026-55244 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (6th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-55244?
CVE-2026-55244 has a CVSS base score of 5.0 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-55244?
A fix for CVE-2026-55244 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-55244 are linked in the Vendor Advisories panel on this page.

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